Question

which of the following metabolic processes in eukaryotic cells will proceed normally whether oxygen (o₂) is present or absent?
electron transport
glycolysis
the citric acid cycle
oxidative phosphorylation
chemiosmosis

Explanation:

• Electron transport: Requires oxygen as the final electron acceptor in aerobic conditions. Without oxygen, it cannot proceed normally in eukaryotic cells.
• Glycolysis: Occurs in the cytoplasm. It does not require oxygen. It is the first step of both aerobic respiration (when oxygen is present, followed by the citric acid cycle and oxidative phosphorylation) and fermentation (when oxygen is absent).
• The citric acid cycle: Occurs in the mitochondrial matrix. It requires oxygen - indirectly, as it depends on the electron transport chain (which needs oxygen) to regenerate \(NAD^+\) and \(FAD\) (by oxidizing \(NADH\) and \(FADH_2\)).
• Oxidative phosphorylation: Occurs in the inner mitochondrial membrane. It requires oxygen as the final electron acceptor.
• Chemiosmosis: Is part of oxidative phosphorylation (in mitochondria) or photophosphorylation (in chloroplasts). In the context of cellular respiration (mitochondrial chemiosmosis), it requires oxygen for the electron transport chain to create the proton gradient.

Answer:

glycolysis